Electrical circuit breaker



' June 21, 1938. o, K, BECKLER 2,121,243

ELECTRICAL CIRCUIT BREAKER I Filed March 21, 1935 "IdII .40 vide an Patented June 21, 1938 PATENT OFFICE I 2,121,243 nmo'mroar. cmcurr BREAKER,

Oakley K. Beckler, Dallas, 'l'ex., assignor, by

mesne cuts, of seventy-two and one- -half percent to Joseph H. Reynolds, Cisco, Tex, twenty-two and one-half percent to Marion H. Rowe, and live percent to Jack A. Schley, both of Dallas, Tex.

, Application March 21, 1935, Serial No.' 12,155

3 Claims. (Cl. 200-116) This invention relates to new and useful improvements in electrical circuit breakers.

One object of the invention is to provide an improved ,circuit breaker which is arranged to be 5 connected in an electrical circuit and which will efficiently break the circuit in caseof an overload or short circuit, being particularly adapted for use in motorvehicles.

An important object of the invention is to provide an improved circuit breaker including a clip formed of thermostatic metal, which is arranged to engage two electrical contact points whereby the electrical circuit is closed, the current flowing through said clip; thus, an overload or short in the circuit will act upon the clip. .to heat the same, thereby causing an expansion thereof which releases the clip from the'contact points to break the circuit, this breaking of the circuit permitting the clip to cool andreturn'to its normal unexpanded position, whereby it may again be engaged with the contacts to again close the circuit.

Another object of the invention is to provide an improved clip of thermostatic metal in a circuit breaker, which is arranged to engag electrical contacts to close a circuit, and means for imparting a snap action to the disengagement of said clip fromsaid contacts when an overload or short occurs in the circuit and expands the clip, whereby a positive and quick breaking of the circuit is had; said means also holding the clip in a disengaged position until a manual op-. eration again engages the clip with the contacts.

A further object of the invention is to provide an improved circuit breaker for the electrical circuit of a motor-vehicle, which may be used indefinitely and which is cheap in manufacture and simple in construction. a t

Still another object of the invention is to .pro-

proved circuit breaker, as described above, w ch may be mounted in the usual clips provided in the motor vehicles for the ordinary glass tubular fuse now in general use.

A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawing, in

which an example of theinvention is shown, and I another form of spring for the clip, 1

Figure 8 is a side elevation of another formof the invention, Figure 9 is an elevation taken at right angles to Figure 8,

Figure 10 is an elevation taken from the oppo-' 1 site side to that shown in Figure 9, Q

Figure 11 is atransverse vertical sectional view taken on the line ll-ll of Figure 9, s

Figure 12 is a view similar to Figure 8, showing the circuit breaker positioned within the usual 20 spr n c i a Figure 13 is a horizontal cross-sectional view, taken on the line IL-l3 of Figure 9. r

In the drawing, the numeral l0 designates a support; which may be the rear side of the in- 25 strument panel of a motor vehicle, or other suitable place on which the circuit breaker ll may be mounted. The circuit breaker is connected in the electrical circuit of the motor vehicle and includes an elongated bar 12, which is preferably 3*" made of bakelite, although it maybe constructed oi any suitable electrical non-conducting material. The bar has a pair of metal plates I 3 disposed along its inner side. The plates may be constructed of copper or other electrical con- 35 In to fasten the bar to the support In. Suitable insulating washers Ill are inserted between the support and plates to insulate the support from the latter.

Theinner end of each plate is. cut out at II so that when the 'plates are positioned on the bar as shown in Figure 4, their inner ends'will lie parallel to each other with 'aspace therebetween. It is'pointed out that there is no electrical connection between the plates. One of the 50 plates is connected by a wire A to one side of the electrical circuit of the motor vehicle, while I Y the other plate is-connected by a wire B to the opposite'slde of the circuit. However, since there is no connectionbetween the plates, it is obvious that electrical current can not pass from one plate to the other.

For closing the electrical circuit between the plates, a metal clip I6 is provided. This clip is constructed of thermostatic metal, which is a fabrication of two metals having widely different coeillcients of thermal expansion. When a metal so formed is heated, it will bend away from the high expansive side, that is, if brass and steel are used in the construction of the metal, the heating thereof will cause the metal to bend away from the side on which the brass is located because there is an increased expansion of the brass with relation to the steel. Thermostatic metal may be purchased on the open market and no claim is made to its particular qualities, the foregoing explanation being merely for the sake of clarity.

As clearly shown in Figures 1, and 6, the thermostatic metal clip i6 is yoke-shaped and straddles the central portion of the bar. The lower ends of the arms ll of the yoke are crimped to form lugs l1, whereby when the clip is forced downwardly over the bar (Figure 6), the lugs will engage the underside of the plates ll. .Since the clip is located centrally of the bar II, it is obvioils that one of the arms ll of the clip will engage the inner end of one of the plates i2, while the other arm will engage the inner end of the other plate, whereby the clip serves to electrically connect the plates, thereby closing the circuit between the wires A and B.

A flat spring ll (Figures 1, 2, 5 and 6) has one end secured to the outer face of the bar H by the rivet II. A suitable insulating washer ll surrounds the rivet II, to insulate said rivet from the spring. The spring overlies the bar and extends to the central portion thereof, having its other end secured to the underside of the top of the yoke-shaped clip 16 by a rivet 20. A suitable washer 2| of non-conductive material insulates the spring from the yoke. The rivet also serves to secure a thumb disk 22 of electrical non-conductive material to the outer end of the clip.

As clearly shown in Figures 1 and 2, the flat spring is formed to exert its tension to force the yoke outwardly from the bar. The tension of this spring is slight, being only suillcient to move the ends of the arms of the yoke outwardly from the plates l2, when the lugs II disengage, as shown in Figure 2.

It is pointed out that in forming the yokeshaped clip II, the arms I! are positioned to snugly engage the sides of the bar l2. Therefore, when the clip is moved downwardly and the lugs I'l engage beneath the plates l2, the resiliency of the metal is sufllcient to retain the lugs in engagement against the tension of the spring ll. Therefore, when the yoke is depressed to this position- (Figure 6) the electrical circuit between the wires A and B is closed, the current passing from one plate It to the other plate through the clip.

The thermostatic metal of which the yoke is constructed is made to carry a certain current. Thus, whenever an overload or short occurs in the electrical circuit, the clip is heated. This heating causes an expansion of the clip.' The metal having the greatest expansion of the two metals comprising the clip is located on the inner side of said clip so that upon heating. the arms oi the clip will bend outwardly, as shown by dotted line in Figure 6. As soon as these arms have bent sufllciently to permit the lugs I! to clear the edges of the plates, the spring I8 will immediately move the clip outwardly to the position shown in Figure 2, whereby the ends of the arms 16' of said clip are out of alinement with the plates. The spring I! imparts a snap action to the disengagement of the clip from the plates. As soon as the arms move away from the plates due to the heating, as described, the electrical circuit is broken.

As soon as electricity ceases to pass through the clip, the metal therein will immediately cool and the arms l6 will move inwardly to their normal position. This will cause said arms to engage the sides of the bar l2 when the thumb disk 22 is pressed. At this time, however, the electrical circuit is still broken because the spring It has moved the clip outwardly a sufficient distance to move the ends of the arms l6 of said clip out of alinement with the edge of the plate. The parts remain in this position until the operator depresses the disk 22 and clip secured thereto. This depression causes the lugs H to again engage the inner side of the plates to again close the electrical circuit between said plates.

Since the life of the thermostatic metal is practically indefinite, it is obvious that a circuit breaker which will last during the life of the vehicle to which it is attached, is provided. Since the voltage 0! the electrical circuit of a motor vehicle is comparatively low, the danger of arcing as the clip engages and disengages the plates is practically negligible. However, if there were any tendency of arcing, the snap action in both engagement and disengagement of the arms IS with the plates, would eliminate this. Although,

vI have shown the clip as connected with the flat spring l8, a coiled spring 25 (Figure '7) could be employed. In such case the rivet 20 would be extended to slide through an opening 25 in the bar 12 and plate i3. The coiled spring surrounds the rivet being conflned between the upper end of the clip and the bar, exerting its tension upwardly at all times. The operation of the clip is the same.

In Figures 8 to 13, I have shown another form 01 the invention. This form is adapted to be used in the usual spring clips 21, which are mounted on the inner side of the instrument panel 28 of a motor vehicle and which receive the usual glass tubular fuse. In constructing this form, a cylindrical body 20 of bakelite has two curved plates 3| mounted on its inner side in the same way as the plates I! are secured to the bar l2, that is, there is no electrical connection therebetween. The outer end of each plate, however, is constructed to completely encircle the ends of the body 30 so that when the body is inserted into the clips, a good contact is made. Centrally of the body, the clip i6 is mounted in the same way as the form shown in Figure 7. This form may be used in the motor vehicles now on the market and since it operates in the same way as the form shown in Figures 1 to 6, a detailed description is deemed unnecessary.

It is obvious that a circuit breaker which is simple in construction and cheap in manufacture is provided. Its operation is positive since it depends on the heating of the thermostatic clip,

which will occur any time an overload or short occurs in the circuit. The snap action is an important featureas it assures a positive make and break of the circuit, the one by pressing the thumb disk 22 and the other by the action of the bi-metal element. Although the breaker has been shown as used on the circuit of a motor vehicle,

it is obvious that it may be used where found desirable.

What I claim and desire to secure by Letters Patent is:

1. A circuit breaker including, an elongated body of non-conducting material, a pair of electrical contacts mounted on the body and having their inner ends extending in parallel spaced relationship at the central portion of the body, a unitary bl-metallic circuit closing element operable in one direction to move into gripping engagement with the contacts to close the electrical circuit therebetween, and a. spring element secured to the bi-metallic element and adapted to be placed under tension when said bi-metallic element is in circuit closing position, whereby said spring element effects an immediate disengagement of the bi-metallic element from the contacts when said bi-metallic element is overheated due to an overload or short circuit.

2. A circuit breaker including, an elongated body of electrical non-conducting material, a pair of electrical contacts mounted on the body and having their inner ends extending in parallel relation one on each side of an intermediate portion of said body, a yoke-shaped bi-metallic clip straddling the inner-ends of the contacts for engaging said contacts to close an electrical circuit therebetween, the spacing between the yoke arms being such that said-arms normally frictionally grip the contacts, and spring means engaging the yoke for effecting a disengagement of the yoke arms from the contacts and operable when the clip is heated due to an overload or short circuit.

3. A circuit breaker including, a cylindrical body of electrical non-conducting material insertable in cartridge gripping spring clips, a pair of electrical contacts onsaid body with their outer ends engaging within said clips, and their ends extending in parallel spaced relationship at an intermediate portion of the body, a bi-metallic yoke having its arms spaced from each other so as to frictionally engage and grip said contacts to close the circuit therebetween, and spring-actuated resett'able means engaging the yoke for disengaging the arms of said yoke from the contacts to break the circuit when the yoke is heated due to an overload or short circuit.

l OAKLEY K. BECKLER. 

